Apparatus for encoding and decoding audio signal and method thereof

• US 8,082,157 B2
• Filed: 06/30/2006
• Issued: 12/20/2011
• Est. Priority Date: 06/30/2005
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Pang, Hee Suk, Oh, Hyen O, Kim, Dong Soo, Lim, Jae Hyun, Jung, Yang Won, Yoon, Sung Young
• Primary Examiner(s): AZAD, ABUL K
• Application Number:
  US11/994,317
• Publication Number:
  US 20080208600A1
• Time in Patent Office: 1,999 Days
• Field of Search: 704500-504, 704/225, 381/106, 333/14
• US Class Current: 704/500
• CPC Class Codes: G10L 19/008 Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing

Abstract

A method and/or apparatus for encoding and/or decoding an audio signal is disclosed, in which a downmix gain is applied to a downmix signal in an encoding apparatus which, in turn, transmits, to a decoding apparatus, a bit stream containing information as to the applied downmix gain. The decoding apparatus recovers the downmix signal, using the downmix gain information. A method and/or apparatus for encoding and/or decoding an audio signal is also disclosed, in which the encoding apparatus can apply an arbitrary downmix gain (ADG) to the downmix signal, and can transmit a bit stream containing information as to the applied ADG to the decoding apparatus. The decoding apparatus recovers the downmix signal, using the ADG information. A method and/or apparatus for encoding and/or decoding an audio signal is also disclosed, in which the method and/or apparatus can also vary the energy level of a specific channel, and can recover the varied energy level.

Claims

1. A method for decoding an audio signal, the method comprising:

receiving a downmix signal and a spatial information signal including spatial information and channel gain information, wherein the channel gain information comprises a low frequency enhancement (LFE) gain and a surround gain;

generating a multi-channel audio signal, including a LFE channel signal and at least one surround channel signal, by applying the spatial information to the downmix signal; and

generating a modified multi-channel audio signal by applying the channel gain information to the multi-channel audio signal in a time domain,

wherein the step of applying the channel gain information includes;

applying the LFE gain to the LFE channel signal; and

applying the surround gain to the at least one surround channel signal.

2. The method of claim 1, wherein the step of generating the multi-channel audio signal comprises:

generating the multi-channel audio signal in a frequency domain.

3. The method of claim 1, wherein the step of applying the channel gain information to the multi-channel audio signal comprises:

applying the channel gain information to entire frames of the LFE channel signal or the at least one surround channel signal.

4. The method of claim 1, wherein the channel gain information is contained in a header region of the spatial information.

5. The method of claim 1, further comprising:

obtaining a downmix gain from the spatial information signal; and

modifying an energy level of entire frames of the downmix signal based on the downmix gain.

6. The method of claim 5, wherein the downmix gain is contained in a header region of the spatial information.

7. A method of encoding an audio signal, the method comprising:

receiving a multi-channel audio signal including a low frequency enhancement (LFE) channel signal and at least one surround channel signal;

generating a modified multi-channel audio signal by modifying an energy level of the LFE channel signal and the at least one surround channel signal included in the multi-channel audio signal;

generating channel gain information based on the modified energy level and the multi-channel audio signal;

generating a downmix signal by downmixing the modified multi-channel audio signal; and

generating spatial information to upmix the downmix signal, based on the multi-channel audio signal,

wherein the channel gain information includes a surround gain indicating a gain for the at least one surround channel signal and a LFE gain indicating a gain for the LFE channel signal.

8. An apparatus for decoding an audio signal, comprising:

a demultiplexer configured to extract, from a received signal, a downmix signal and a spatial information signal including spatial information and channel gain information,

wherein the channel gain information comprises a low frequency enhancement (LFE) gain and a surround gain;

a multi-channel generating unit configured to generate a multi-channel audio signal, including a LFE channel signal and at least one surround channel signal, by applying the spatial information to the downmix signal; and

a channel level modifying unit configured to generate a modified multi-channel audio signal by applying the channel gain information to the multi-channel audio signal in time domain,

wherein the channel level modifying unit is configured to apply the LFE gain to the LFE channel signal and apply the surround gain to the at least one surround channel signal.

9. The apparatus of claim 8, wherein the multi-channel generating unit is configured to generate the multi-channel audio signal in a frequency domain.

10. The apparatus of claim 8, wherein the channel level modifying unit is configured to apply the channel gain information to entire frames of the LFE channel signal or the at least one surround channel signal.

11. An apparatus for encoding an audio signal, comprising:

a specific channel level processing unit configured to generate a modified multi-channel audio signal by modifying an energy level of a low frequency enhancement (LFE) channel signal and at least one surround channel signal included in a multi-channel audio signal;

a downmixing unit configured to downmix the modified multi-channel audio signal to form a downmix signal; and

a spatial information generating unit configured to generate channel gain information based on the modified energy level and the multi-channel audio signal, and generate spatial information to upmix the downmix signal, based on the modified multi-channel audio signal,

wherein the channel gain information includes a surround gain indicating a gain for the at least one surround channel signal and a LFE gain indicating a gain for the LFE channel signal.